There is a need for providing a flexible dense wavelength division multiplexing (DWDM) and switching architecture, eg for use in network node systems.
Traditional architectures centre around a fixed link between line interfaces and trunk interfaces to channels of the DWDM. Such architectures have the disadvantage that failure of one of the DWDM channels will effectively cut out one of the line connections, ie service to a particular subscriber is disrupted until the faulty DWDM channel has been “repaired”, eg by replacing a DWDM laser.
The present invention seeks to provide a multiplexer structure which addresses this problem.